1. Field of the Invention
The present invention relates to the technical field of backlight local dimming and, more particularly, to a method and apparatus of compensating image in a backlight local dimming system.
2. Description of Related Art
Multiple backlight sources are typically used in the current liquid crystal display (LCD) device for controlling a plurality of display areas of the LCD device to save the power. The backlight local dimming indicates that the backlight sources of the LCD device are adjusted according to the image brightness, but not in a state of full brightness.
Typically, the backlight sources of the LCD device are at full brightness. The display of a dark frame is achieved by reducing the transmittance of liquid crystal, which has no help for reducing the power consumption. By contrast, the backlight local dimming allows the brightness of backlight source to be varied with dark and light frames, so the brightness of backlight source is reduced when a dark frame is displayed. Thus, the entire amount of power consumption of the backlight is reduced.
In addition to the power consumption reduction, the backlight local dimming can also improve the frame quality of the LCD device. For example, the high dynamic contrast is dramatically increased. In addition, the backlight local dimming can be applied in the backlight sources to further increase the number of gray scales on the LCD device.
In the entire power consumption of an LCD device, the backlight module typically occupies the largest proportion, about 66%. Further, the developing LCD devices trend to a large size, so the frames to be displayed require higher brightness, which consumes more power. In this case, from a viewpoint of power saving, the backlight local dimming can relatively reduce the amount of power consumption on the large LCD device. In addition, the increase on the frame quality provides the optimal solution for the current backlight sources.
A typical backlight local dimming can increase the frame contrast and reduce the power consumption, but the inappropriate backlight decision and image compensation may reduce the image quality, including color washout, ripples, no control of highlight detail, flickers, and inappropriate backlight on dark and light frames. Therefore, it is desirable to provide an improved backlight local dimming to mitigate and/or obviate the aforementioned problems.